I changed the oil the other day and spotted an area where a leak had spread onto the subframe and surrounding area. I had a good look round and it didn't seem to be oil and concluded it was power steering fluid seeping from somewhere.

I couldn't find where it was coming from, so it must be a seal weaping.

Sure enough the power steering fluid was low. I drained out what I could from the reservoir and fiilled it with some Leak Stop fluid.

It claims to guarantee to stop leaks which seems a bold claim.

Has anyone any experience of using this stuff and having any joy from it?

Haven't used the stuff your talking about but i had a leak on my m59 and it was coming out of where the pinion is located near where it meets the column/uj it was seeping out the top and required a new rack.